U.S. patent application number 15/328302 was filed with the patent office on 2017-07-27 for dishwasher having a liquid transportation line.
The applicant listed for this patent is Harald Disch, Markus Heidt, Philipp Klumpp, Norbert Litterst. Invention is credited to Harald Disch, Markus Heidt, Philipp Klumpp, Norbert Litterst.
Application Number | 20170209020 15/328302 |
Document ID | / |
Family ID | 54056304 |
Filed Date | 2017-07-27 |
United States Patent
Application |
20170209020 |
Kind Code |
A1 |
Disch; Harald ; et
al. |
July 27, 2017 |
DISHWASHER HAVING A LIQUID TRANSPORTATION LINE
Abstract
A dishwasher, in particular a commercial single-tank dishwasher
or commercial multi-tank dishwasher, for washing washware includes
a liquid transportation line (100) with at least one supply line
for supplying liquid at a first temperature and comprising at least
one discharge line for discharging liquid at a second temperature,
wherein the supply line and the discharge line run coaxially in
relation to one another, so that either the supply line or the
discharge line forms an internal line (10) which runs in the
direction of extent of the liquid transportation line (100) within
the respectively other supply line or discharge line which for its
part forms an external line (20), and thereby form a countercurrent
heat exchanger.
Inventors: |
Disch; Harald; (Elzach,
DE) ; Klumpp; Philipp; (Lahr, DE) ; Heidt;
Markus; (Kehl, DE) ; Litterst; Norbert;
(Offenburg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Disch; Harald
Klumpp; Philipp
Heidt; Markus
Litterst; Norbert |
Elzach
Lahr
Kehl
Offenburg |
|
DE
DE
DE
DE |
|
|
Family ID: |
54056304 |
Appl. No.: |
15/328302 |
Filed: |
August 27, 2015 |
PCT Filed: |
August 27, 2015 |
PCT NO: |
PCT/US2015/047093 |
371 Date: |
January 23, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A47L 15/4217 20130101;
A47L 15/4212 20130101; A47L 15/4291 20130101 |
International
Class: |
A47L 15/42 20060101
A47L015/42 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 2, 2014 |
DE |
10 2014 217 503.8 |
Claims
1. A dishwasher for washing washware, wherein the dishwasher has a
liquid transportation line comprising at least one supply line for
supplying liquid at a first temperature and comprising at least one
discharge line for discharging liquid at a second temperature,
wherein the supply line and the discharge line run coaxially in
relation to one another, so that one of the supply line or the
discharge line forms an internal line which runs in direction of
extent of the liquid transportation line within the other of the
supply line or discharge line which for its part forms an external
line, and thereby form a countercurrent heat exchanger.
2. The dishwasher as claimed in claim 1, wherein the internal line
has a wall which is formed from a material which has a high
specific thermal conductivity, and wherein the external line has a
wall which is formed from a material which has a low specific
thermal conductivity.
3. The dishwasher as claimed in claim 2, wherein the material of
the wall of the internal line is a metal and/or wherein the
material of the wall of the external line is a plastic
material.
4. The dishwasher as claimed in claim 1, wherein the liquid which
can be discharged by means of the discharge line is waste water and
is supplied directly to a waste water system.
5. The dishwasher as claimed in claim 1, wherein the liquid which
can be supplied by means of the supply line is fresh water and is
drawn directly from a drinking water system.
6. The dishwasher as claimed in claim 1, wherein the external line
is the supply line, and wherein the first temperature is at least
30 K lower than the second temperature.
7. The dishwasher as claimed in claim 1, wherein a continuous
intermediate wall is provided between the wall of the internal line
and the wall of the external line.
8. The dishwasher as claimed in claim 7, wherein the intermediate
wall bears against the internal line at least in regions.
9. The dishwasher as claimed in claim 7, wherein at least one
channel which runs in the direction of extent of the liquid
transportation line is formed between the intermediate wall and the
internal line wherein the at least one channel is connected to the
surrounding atmosphere in a pressure-related manner at at least one
line ends of the liquid transportation line.
10. The dishwasher as claimed in claim 9, wherein the at least one
channel is connected to a sensor device in order to identify liquid
escaping from the internal line into the channel.
11. The dishwasher as claimed in claim 10, wherein the sensor
device is in the form of a pressure sensor.
12. The dishwasher as claimed in claim 10, wherein the sensor
device is in the form of an optical sensor which is arranged at at
least one of the line end of the liquid transportation line, in
order to identify liquid escaping from the at least one
channel.
13. The dishwasher as claimed in claim 1, wherein a a T-shaped
connection piece which is composed of plastic, having a connection
for the external line and having a connection for the internal line
is provided at at least one of the line ends of the liquid
transportation line.
14. A dishwasher, comprising: at least one tank, and a liquid
transportation line comprising at least one supply line and at
least one discharge line, wherein the supply line supplies liquid
at a first temperature into the dishwasher and the discharge line
discharges liquid at a second temperature from the dishwasher,
wherein the supply line and the discharge line run coaxially in
relation to one another, wherein one of the supply line or the
discharge line forms an internal line and the other of the supply
line or the discharge line forms an external line, wherein the
internal line runs along the liquid transportation line and within
the external line to form a countercurrent heat exchanger between
the internal line and the external line.
15. The dishwasher as claimed in claim 14, wherein a continuous
intermediate wall is provided between a wall of the internal line
and a wall of the external line.
16. The dishwasher as claimed in claim 15, wherein the intermediate
wall bears against the internal line at least in regions.
17. The dishwasher as claimed in claim 16, wherein at least one
channel runs along the liquid transportation line and is formed
between the intermediate wall and the internal line, wherein the at
least one channel is fluidly connected to ambient atmosphere.
18. The dishwasher as claimed in claim 17, wherein the at least one
channel is connected to a sensor device in order to identify liquid
escaping from the internal line into the channel.
19. The dishwasher as claimed in claim 17 wherein the at least one
channel is formed as a groove along an inner surface of the
intermediate wall.
Description
TECHNICAL FIELD
[0001] The present invention relates to a dishwasher, in particular
a commercial single-tank dishwasher or commercial multi-tank
dishwasher, for washing washware.
BACKGROUND
[0002] In the field of commercial dishwashers--be they
conveyor-type dishwashers having several liquid tanks or hood-type
dishwashers or other stationery machines with only one liquid
tank--it is necessary for fresh water to be introduced into the
system at least at one point and for used washing water to be
discharged from the system at least at one point. Since the fresh
water is usually drawn from the public drinking water system or the
like, it is at a comparatively low temperature which is not
suitable for all dishwashing zones or dishwashing processes.
Therefore, final rinsing can of course be performed with
comparatively cold fresh water; however, at the latest when the
water is intended to be used as cleaning water, for example, in the
next dishwashing section of the washing water cascade in the case
of a conveyor-type dishwasher or at a corresponding program point
in the case of a batch dishwasher and, for example, with a
detergent or the like admixed, low washing water temperatures of
this kind are no longer sufficient.
[0003] If the washing water is now heated to the required
temperature as is customary, the question arises of whether the
heat remaining in the washing water after said washing water is
used, for example by partial or complete replacement of the used
washing water with fresh water, can be used.
[0004] In the case of commercial hood-type dishwashers,
approximately 50% of the supplied thermal energy is discharged as
lost heat in the form of heated waste water.
[0005] The remainder of the supplied thermal energy remains in the
washware or is lost as a result of vapor discharge or the like.
[0006] It is known in the art to use the thermal energy in the
waste water, before said waste water is discharged to the waste
water system, by means of a heat exchanger in such a way that this
heat in the outflowing waste water--physically separately from the
fresh water--is at least partially transmitted to the supplied
fresh water by means of a heat exchanger. The conventional
solutions now have the disadvantage that they sometimes do not
function reliably enough and, in particular, the waste water
remains at a comparatively high temperature when introduced into
the waste water system, as a result of which less thermal energy is
emitted to the supplied fresh water. This is the result of, for
example, heat exchangers which are composed of plastic materials
often being used, these having a low thermal conductivity on
account of the material used. In addition, plate-type heat
exchangers or the like which are used can become clogged if the
washing water is heavily soiled (food residues), wherein these food
residues collect between the plates of the plate-type heat
exchanger and block the liquid channel.
[0007] An excessively high waste water temperature is also
disadvantageous in that it is not possible to comply with any
existing local standards. For example, the US "Uniform Plumbing
Code" specifies a maximum waste water temperature of 140.degree.
Fahrenheit (60.degree. C.) wherein, if this auxiliary limit cannot
be complied with, cold fresh water is often supplied to the waste
water in order to comply with the required maximum waste water
value.
[0008] The invention is therefore based on the object of specifying
a dishwasher having a corresponding heat recovery device which
operates more reliably than conventional solutions and at the same
time has a good energy yield and can be produced in a
cost-effective manner.
SUMMARY
[0009] The object is achieved, in particular, by a dishwasher for
washing washware, wherein the dishwasher has a liquid
transportation line comprising at least one supply line for
supplying liquid at a first temperature and comprising at least one
discharge line for discharging liquid at a second temperature,
wherein the supply line and the discharge line run coaxially in
relation to one another, so that either the supply line or the
discharge line forms an internal line which runs in the direction
of extent of the liquid transportation line within the respectively
other supply line or discharge line which for its part forms an
external line, and thereby form a countercurrent heat
exchanger.
[0010] In this case, the direction of extent of the liquid
transportation line is defined by the flow path of the fluid which
is to be supplied or to be discharged and does not necessarily have
to run in a straight line.
[0011] The fact that the supply line and the discharge line run
coaxially in relation to one another results in the particular
advantage that, by forming a countercurrent heat exchanger, heat
can be transferred in a reliable and efficient manner in such a way
that the waste water, which is intended to be discharged by means
of the discharge line, is then at a sufficiently low temperature.
At the same time, the solution of forming the heat exchanger by
coaxial construction from the supply line and the discharge line
and realizing said heat exchanger in countercurrent form is very
cost-effective.
[0012] Advantageous developments of the solution can be
implemented.
[0013] For example, it is provided that the internal line has a
wall which is formed from a material which has a high specific
thermal conductivity, and that the external line has a wall which
is formed from a material which has a low specific thermal
conductivity.
[0014] This has the result that good heat exchange can take place
between the two fluids (fresh water and waste water) which flow in
countercurrent in the interior of the liquid transportation line,
wherein undesired emission of heat to the outside is suppressed at
the same time. In this connection, it is preferably provided that
the material of the wall of the internal line is copper. Copper has
a high specific thermal conductivity in the range of from
approximately 240 to 400 W/(m.sup.2K). In this connection, it can
be provided, as an alternative or in addition, that the material of
the wall of the external line is a plastic material. The specific
thermal conductivity of additive-free plastics lies, for example,
in the range of between 0.1 and 0.6 W/(m.sup.2K), while plastics
with additives have, for example, a specific thermal conductivity
of approximately 1 to 10 W/(m.sup.2K).
[0015] According to a further aspect, it is provided that the
liquid which can be discharged by means of the discharge line is
waste water and is preferably supplied directly to the waste water
system. Since, owing to the solution provided herein, this waste
water is at a temperature which is suitable for direct introduction
in accordance with strict standards such as, for example, the US
"Uniform Plumbing Code" and is generally less than 60.degree. C.,
it is, owing to the solution provided herein, no longer necessary
to supply fresh water to the waste water for cooling purposes in
order to comply with this maximum temperature. According to a
further aspect, it is provided that the liquid which can be
supplied by means of the supply line is fresh water and is
preferably drawn directly from the drinking water system.
[0016] This results in the particular advantage of the solution
provided herein that this fresh water which is drawn directly from
the drinking water system and is usually at a relatively low
temperature of, for example, 15.degree. C. or the like does not
first have to be reheated, but rather can be efficiently heated by
the transfer of heat in the countercurrent heat exchanger.
[0017] According to a further aspect, the external line is the
supply line, and accordingly the internal line is the discharge
line. In other words: the hot water is conducted through the
internal line of the two lines, while the cool fresh water is
introduced into the dishwashing system by means of the external
line. This ensures, in particular in combination with a
corresponding material selection, optimum transfer of heat from the
hot waste water flowing on the inside to the cold fresh water
flowing in the opposite direction on the outside, wherein an
insulating effect is ensured toward the outside, that is to say in
relation to the liquid transportation line toward the outside, at
the same time.
[0018] In this case, it is particularly provided that the first
temperature is lower than the second temperature, and is preferably
30 to 40 K lower, and particularly preferably approximately 45 K
lower, than the second temperature.
[0019] According to a further aspect, it is provided that a
continuous intermediate wall is provided between the wall of the
internal line and the wall of the external line. In this case, it
is preferably provided that the intermediate wall bears against the
internal line at least in regions and preferably by way of more
than half of its surface. In this connection, "continuous" means
that said intermediate wall runs in the direction of extent of the
liquid transportation line substantially as far as the line end,
but there can be correspondingly shortened or lengthened in order
to be able to create a possible connection.
[0020] Sufficiently good heat transfer between the medium flowing
through the internal line and the medium flowing through the
external line is further possible particularly when the
intermediate wall bears against the internal line by way of more
than half of its surface; at the same time however the intermediate
wall provides additional protection to the effect that
unintentional mixing of waste water and fresh water and/or waste
water affecting the fresh water system or the like can be
effectively prevented.
[0021] In this case, it is particularly preferably provided that at
least one channel which runs in the direction of extent of the
liquid transportation direction is formed between the intermediate
wall and the internal line. This at least one channel is connected
to the surrounding atmosphere in a pressure-related manner at at
least one of the line ends of the liquid transportation line. In
other words: this at least one channel forms a leakage gap and, in
the event of a leakage, conducts the escaping liquid to at least
one of the line ends of the liquid transportation line. In this
case, said liquid can be accordingly discharged without there being
any risk of it affecting the fresh water system and as a result
possibly contaminating the fresh water or drinking water
system.
[0022] According to an advantageous development of this aspect, the
at least one channel is connected to a sensor device in order to
identify liquid escaping from the internal line into the channel.
In this case, the sensor device can be in the form of a pressure
sensor. However, at the same time, it is also possible for the
sensor device to be in the form of an optical sensor. An optical
sensor of this kind is preferably arranged at at least one of the
line ends of the liquid transportation line and serves to identify
liquid escaping from the at least one channel.
[0023] Both the pressure sensor and an optical sensor of this kind
enables simple and reliable identification of a leakage of this
kind, wherein, in the event of identification in this way, a liquid
blocking device which separates the fresh water-carrying line
(external line or internal line) from the fresh water system as
soon as a leakage of this kind is identified by means of the
sensor. A blocking device of this kind can be, for example, a
controllable solenoid valve or the like. As a result, it is
possible to reliably suppress an undesired effect (contamination or
the like) on the fresh water system, specifically at an early stage
when a possible leakage is first identified.
[0024] According to a further development, a connection device, in
particular a T-shaped connection piece which is composed of
plastic, is provided at at least one of the line ends of the liquid
transportation line. This connection device has a connection for
the external line and a connection for the internal line. When a
channel is provided in an intermediate wall, a connection for this
at least one channel can preferably additionally be provided.
Simple connection of the coaxial liquid transportation line is
possible by means of a connection piece, in particular T-shaped
connection piece, of this kind.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Exemplary embodiments will be explained in greater detail
below with reference to the drawings, in which:
[0026] FIG. 1: shows a perspective view of a liquid transportation
line for a dishwasher in line with a first embodiment;
[0027] FIG. 2: shows an enlarged region of a line end of the liquid
transportation line from FIG. 1;
[0028] FIG. 3: shows a sectional side view through the line end of
the liquid transportation line shown in FIG. 2 level with a
dishwasher according to the first embodiment;
[0029] FIG. 4: shows a view of the lumen of the line end from FIGS.
2 and 3;
[0030] FIG. 5: shows a perspective view of a liquid transportation
line for a dishwasher according to a second embodiment;
[0031] FIG. 6: shows an enlarged detail of a line end of the liquid
transportation line from FIG. 5;
[0032] FIG. 7: shows a further enlarged detail of the line end;
[0033] FIG. 8: shows a sectional side view through the line end
according to FIG. 6; and
[0034] FIG. 9: shows a side view of the lumen of the line end of
the liquid transportation line in FIGS. 5 to 8.
DETAILED DESCRIPTION
[0035] FIG. 1 shows a perspective view of a liquid transportation
line 100 for a dishwasher according to a first embodiment. The
liquid transportation line 100 runs in a meandering manner overall
and has an internal line 10 which is composed of copper pipe and
also has an external line 20 which is composed of a plastic
material. As more clearly shown by the enlarged illustration of the
line end 101 or 102 in FIG. 2, the liquid transportation line 100
is formed such that the internal line 10 in the form of the copper
pipe runs within a corrugated hose which forms the external line
20. The hot waste water is conducted through the metal pipe, that
is to say through the internal line 10, while the cold fresh water
is routed between said metal pipe (internal line 10) and the
corrugated hose (external line 20) in countercurrent. A
countercurrent heat exchanger is formed as a result.
[0036] As is clear from the sectional side view in FIG. 3, a
T-shaped connection piece 50 is provided at one of the two line
ends (101, 102), it being possible for the said T-shaped connection
piece to be connected in a simple manner to a supply or discharge
system by means of a connection 52 for the internal line 10 and by
means of a connection 51, which runs approximately at a 90.degree.
angle to the connection 52, for the external line 20. To this end,
both the connection 51 for the external line and the connection 52
for the internal line have latching lugs, which correspond to a
connection plug, or the like for locking purposes.
[0037] Therefore, the structure shown in side view in FIG. 4 is the
result of looking at the line end from the top. The internal line
10 is therefore limited by a corresponding wall 11, as a result of
which a lumen 12 for the liquid transportation is formed in the
interior of this wall. The external line 20 accordingly has a wall
21, as a result of which a corresponding lumen 22 of the external
line 20 is produced coaxially to the lumen 12 of the internal line
10. The hot waste water is conducted away through the lumen 12 of
the internal line 10, while the cooler fresh water, which is
generally approximately 40 K cooler, is supplied in countercurrent
through the lumen 22 of the external line 20. Particularly
effective heat transfer between the media flowing in the lumens 12,
22 is possible in this way.
[0038] Analogously to the illustration in FIG. 1, FIG. 5 shows a
perspective view of a liquid transportation line 100, but in this
case of a dishwasher in line with a second embodiment.
[0039] As is clear from the enlarged perspective illustration in
FIG. 6, an internal line 10 which is composed of copper pipe and an
external line 20 which is composed of a corrugated plastic hose are
again provided, but, in line with the second embodiment, an
intermediate wall 30 is additionally provided in the region of the
wall 11 of the internal line 10. The intermediate wall 30 is
formed, for example, by pressing with the internal line 10 and is
formed from a material which further allows good heat transfer
between the lumen 12 of the internal line 10 and the lumen 22 of
the external line 20. As is more clearly shown in the illustrations
in FIGS. 7 (perspective enlarged illustration of internal line 10
and intermediate wall 30) and FIG. 9 (plan view of the lumen), the
intermediate wall 30 bears against the wall 11 of the internal line
10 by way of a large portion of its surface (more than half of its
surface). However, a large number of channels, which are denoted 31
altogether, are formed in the other regions.
[0040] In other words: adjacent regions 32 of the intermediate wall
30 are provided on the internal line 10, wherein channels 31 which
each run in the direction of extent of the liquid transportation
line 100 are provided between these adjacent regions 32. These
channels 31 are connected to the surrounding atmosphere in a
pressure-related manner at at least one of the line ends 101 and/or
102 of the liquid transportation line 100 in the dishwasher in line
with the second embodiment.
[0041] A sensor device, for example an optical sensor (not
illustrated), which serves to identify undesired leakages and the
like, is provided at the respective line end 101 or 102. It goes
without saying that it is equally possible to provide a plurality
of intermediate walls 30. In the event of a leakage, in particular
a leakage in the internal line 10 which transports the hot waste
water in line with the embodiments 1 and 2, the escaping liquid is,
in the case of this leakage, therefore conducted to the line end
101 or 102 where it can be collected without the possibility of
contamination due to said escaping liquid affecting the fresh water
system or the like. At the same time, a signal can be triggered by
means of the sensor (not illustrated) by way of a corresponding
control device or the like, said signal closing a solenoid valve
(likewise not illustrated) or the like as soon as a leakage is
identified. In this case, this solenoid valve is provided between
the connection 51 for the external line 20 and the fresh water
system.
[0042] Owing to the solution provided herein, it is possible to
provide an effective and low-cost possible way of ensuring heat
recovery in a dishwasher, in particular a commercial single-tank
dishwasher or commercial multi-tank dishwasher, wherein the waste
water temperature of the waste water which is to be introduced is
low enough to be able to meet strict standards, such as the US
"Uniform Plumbing Code" for example, at the same time. At the same
time, in particular when an intermediate wall 30 is provided,
pressure-related compensation of the channels 31 which are arranged
therebetween is provided at the same time, as is likewise required,
for example, by the "Uniform Plumbing Code".
[0043] However, owing to the particular construction, in particular
owing to the adjacent regions 32, effective heat transfer between
the medium flowing in the internal line and the medium routed in
countercurrent in the external line is then possible with the
proposed coaxial construction. As a result, hot waste water which
is at, for example, 60.degree. C. is cooled to below 50.degree. C.
in said countercurrent heat exchanger during a normal dishwashing
cycle, as a result of which an otherwise usually elevated
consumption of fresh water on account of cold water being admixed
with said hot waste water before it is introduced into the waste
water system is dispensed with.
[0044] It should be noted here that all described features of the
embodiments have value in combination or on their own. It is to be
clearly understood that the above description is intended by way of
illustration and example only, is not intended to be taken by way
of limitation, and that other changes and modifications are
possible.
LIST OF REFERENCE SYMBOLS
[0045] 10 Internal line [0046] 11 Wall of the internal line [0047]
12 Lumen of the internal line [0048] 20 External line [0049] 21
Wall of the external line [0050] 22 Lumen of the external line
[0051] 30 Intermediate wall [0052] 31 Channel [0053] 32 Adjacent
region of the intermediate wall [0054] 50 T-shaped connection piece
[0055] 51 Connection for the external line [0056] 52 Connection for
the internal line [0057] 100 Liquid transportation line [0058] 101
First line end [0059] 102 Second line end
* * * * *